Reliable, sensitive, and accessible methods to detect colorectal cancer biomarkers can improve early screening. MicroRNA-126 (miRNA-126) is a colorectal cancer–related microRNA of interest for diagnostic applications. The authors present a visual detection platform designed for label-free measurement of miRNA-126 with potential utility in rapid on-site screening and preliminary point-of-care testing (POCT).
This study reports the covalent immobilization of a fluorogenic RNA aptamer, Pepper RNA, modified with an acrydite group (acrydite-Pepper), into a hydrogel matrix via photopolymerization. The acrydite group enables incorporation of the RNA into the polymer network during light-driven polymer formation, producing a Pepper RNA functionalized hydrogel kit.
The immobilized Pepper RNA is presented as serving dual functions within the hydrogel: it acts both as the molecular capture probe for the target miRNA and as the fluorescent signal-generating probe. By embedding the RNA directly into the hydrogel, the authors aim to create a stable, user-friendly detection module that can be handled and read out without additional labeling steps.
Detection is based on a target-triggered fluorogenic RNA switch mechanism. The functionalized Pepper RNA is designed to undergo a conformational change upon hybridization with complementary miRNA-126 through canonical Watson-Crick base pairing. This conformational rearrangement converts the Pepper RNA from a non-fluorescent or weakly fluorescent state into a fluorescent, “light-up” conformation, producing an observable optical signal.
Because the Pepper RNA acts as both capture and reporter, the approach is label-free: the target itself triggers the formation of the fluorescent structure rather than relying on externally attached fluorophores or enzymatic amplification. The authors highlight that this single-molecule dual-function design simplifies the assay workflow and reduces reagent requirements.
The reported analytical sensitivity of the hydrogel kit varies by detection instrument. Using fluorescence microscopy as the readout, the platform exhibited a limit of detection (LOD) of 23.8 pM for miRNA-126. When measured with a microplate reader, a higher sensitivity was achieved with an LOD of 0.53 pM. These values indicate that instrument choice affects measurable sensitivity and that the system can reach sub-nanomolar detection when coupled to sensitive plate-based fluorescence detection.
The abstract emphasizes that the platform is suitable for rapid and sensitive on-site detection, but specific details about assay time, dynamic range, specificity against non-target miRNAs, or performance in clinical or complex biological matrices were not reported in the source abstract and therefore cannot be stated here.
Key practical attributes presented by the authors include simplicity of operation, low cost, and ease of visualization. The hydrogel format with immobilized Pepper RNA provides a visually interpretable fluorescent signal upon target binding, which supports rapid qualitative assessment. The authors position the kit as a foundation for applications in diluted biological sample analysis and preliminary POCT, where minimal equipment and straightforward workflows are desirable.
Two readout modalities are described: direct fluorescence observation by microscopy (visual, lower sensitivity in this report) and microplate reader measurement (quantitative, higher sensitivity). The distinction suggests flexible deployment depending on available instrumentation — from basic visual checks to more sensitive instrumented reads.
The work describes the first reported covalent incorporation of acrydite-modified Pepper RNA into a hydrogel to create a target-driven fluorogenic RNA switch for label-free detection of miRNA-126. The platform achieved LODs of 23.8 pM (fluorescence microscopy) and 0.53 pM (microplate reader), and is presented as simple, low-cost, and suitable for on-site or preliminary POCT use.
Limitations and additional performance metrics (for example, assay duration, stability of the hydrogel kit over time, specificity tests versus related miRNAs, validation in clinical samples, and operational protocols) were not detailed in the abstract and therefore are not available from the provided source text. The authors declare no competing financial interests or personal relationships that could have influenced the study.
This summary is based solely on the abstract and bibliographic data from the cited article (Anal Chim Acta. 2026; doi: 10.1016/j.aca.2026.345719; PMID: 42401452). For full experimental methods, validation data, and comprehensive results, consult the full text of the publication.